Proton stability in low-scale extra-dimensional grand unified theories

TL;DR

This paper introduces an extra-dimensional mechanism that suppresses proton decay in grand unified theories, allowing for a lower X-boson mass scale while maintaining proton stability.

Contribution

It presents a novel localization approach in extra dimensions that exponentially suppresses proton decay mediating couplings, enabling lower unification scales.

Findings

Proton decay rate is significantly suppressed in the proposed model.

The mechanism allows for a lower X-boson mass scale without compromising proton stability.

Localization of fermions and gauge bosons in extra dimensions is key to suppression.

Abstract

We propose an extra-dimensional mechanism that adequately suppresses the rate of proton decay mediated by the X-bosons in grand unified theories. The X-bosons and their Kaluza-Klein modes are localized in the extra spatial dimensions due to the kink configuration of the adjoint Higgs multiplet that is responsible for the spontaneous breaking of the unified gauge group while the standard model gauge bosons freely propagate in the bulk. By localizing fermion multiplets apart from the X-bosons in the extra dimensions, the resulting four-dimensional couplings that give rise to proton decay are exponentially suppressed, leading to the longevity of proton even when the mass scale of the X-bosons is much lower than the usual unification scale.